Traditionally, the viewing and editing of electronic documents—such as word processing documents, spreadsheets, and presentations—was done using specific software applications installed on a computing device. Recently, online document processing applications have been developed which makes it possible for people to create these documents without having document processing software specially installed. These online applications provide access to the document processing features through an Internet browser. The actual documents are stored on the application server, but may be downloaded locally to a client computing device. Because the documents are stored centrally and are accessed via an Internet browser, it is possible for multiple people to view, edit, and share the document regardless of the hardware and software capabilities of the computing device they are using.
The appearance of the same text in an electronic document may differ from one computing device to another. In particular, the appearance of the same text may differ among various Internet browsers. For example, the height or width of the characters may be different or the line breaks may occur at different points in the text. There are several reasons for these differences. Browsers may have different versions of the same font installed. Browsers may also use different algorithms for kerning (determining the amount of space between characters), layout, sizing, or rendering. Furthermore, some browsers may engage in sub-pixel rendering if the display screen of the computing device allows.
In online document processing applications, uniform appearance of text is important. If the size and line breaks of the text do not appear the same across different computing devices, it can cause confusion among different users who view or edit the document from different computing devices. Current solutions to the uniform text rendering problem generally have relied on having the same display or rendering program installed in each computing device.